This section provides background information related to the present disclosure which is not necessarily prior art.
Multiple-input multiple-output (MIMO) radios typically require two or more separately mounted antennas for optimal MIMO performance. However, mounting two separate internal/embedded antennas in a single enclosure can create issues with correct isolation, polarization, and tuning. Also, many devices in which MIMO radios are desirable may not have the necessary footprint size to accept two separate internal/embedded antennas.
When designing MIMO antennas with smaller profiles, improved isolation (e.g., >15 decibels (dB), etc.) and efficiency across all operating frequency bands, challenges arise for planar inverted-F antennas with quarter-wave designs. In some cases, ground proximity coupling has been applied to flexible planar inverted-F antennas (PIFAs) to achieve improved isolation for a dual band antenna while maintaining total efficiency and max gain.
Separately, a planar inverted-F antenna generally can include a planar radiator or upper radiating patch element having a slot. A lower surface of the PIFA is spaced apart from the upper radiating patch element. First and second shorting elements electrically connect the planar radiator to the lower surface. The PIFA also includes a feeding element electrically connected between the upper radiating patch element and the lower surface. The PIFA may be mounted on a ground plane that is larger than the lower surface of the PIFA.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.